1. Field
Various embodiments of the present invention relate to a power-up signal generation circuit and a semiconductor device including the same.
2. Description of the Related Art
In general, in a semiconductor device, a power-up signal generation circuit generates a power-up signal that initializes the semiconductor device. During operation, the semiconductor device receives a power supply voltage (VDD) through a voltage pad from an exterior. The level of the power supply voltage (VDD) supplied through the voltage pad rises from a predetermined voltage, for example, a ground voltage, to a target level with a predetermined slope.
The internal circuit of the semiconductor device performs various operations by using the power supply voltage (VDD). When the power supply voltage (VDD) is used for the operations before it has been stabilized, a concern may occur, such as, a latch-up phenomenon. Thus, the reliability of the semiconductor device may not be guaranteed. In addition, if the internal circuit has not been initialized when the operation of the internal circuit is started, since the signals generated in the internal circuit have uncertain values, an operation error of the semiconductor device is likely to occur.
Therefore, to improve the reliability of the semiconductor device and to prevent an error from occurring in the initial operation of the semiconductor device, the semiconductor device detects the level of the power supply voltage (VDD), which is inputted from the exterior, and allows the power supply voltage (VDD) to be supplied to the internal circuit when the level of the power supply voltage (VDD) rises higher than a predetermined level and is thus stabilized. Further, the semiconductor device initializes the internal circuit before the operation of the internal circuit is started.
A power-up signal is activated when the level of the power supply voltage (VDD) reaches the predetermined level, that is the power-up signal is deactivated until the level of the power supply voltage (VDD) reaches the predetermined level. Thus, the power supply voltage (VDD) may be prevented from being supplied to the internal circuit while it is not stabilized, to protect the internal circuit, and the internal circuit may be initialized before the operation of the semiconductor device is started, to prevent the malfunction of the semiconductor device.
As various kinds of external power supply voltages are used in a semiconductor device, a need for a power-up signal that stably initializes an internal circuit while allowing power supply voltages to be stably supplied to the internal circuit of the semiconductor device, even when speeds at which the levels of the respective power supply voltages rise are different, or an order in which the levels of the respective power supply voltages rise is changed.